Under typical aviation regulations, a deadman switch should be used when performing any pressure fueling or tender filling operation. Deadman switches are designed to safeguard against circumstances or situations that may delay the suspension of fuel flow. Preferably, a deadman switch should not be jammed or bypassed during any fuel transfer operation. Deadman switch types include the electric deadman switch, pneumatic deadman switch (sometimes called an air deadman switch), and combination air/pneumatic types. The deadman switch is actuated, for example through being in the hands of the operator, during a refueling process.
However, a conventional deadman switch provides no method of identifying the operator and so may be used by any person, even those not authorized or trained to use the equipment. Also, conventional equipment controls are often susceptible to jamming or locking in an operating position.
There are also many other circumstances where an authorized person such as an authorized operator needs to be in proximity to the equipment or operation. These circumstances may include any hazardous operation (such as a fueling operation), operation of equipment, medical monitoring situations, operation of equipment requiring some kind of safety interlock system, and the like. Conventional equipment control methods generally do not attempt to identify an authorized operator.